System for Visualizing Data

ABSTRACT

A system for visualising data includes storage means, and a video source arranged for dividing first data to be visualized in one or more banner areas in a plurality of chunks and arranged for outputting the plurality of chunks of the first data to be displayed and for outputting second data to be visualized as a background. A display for visualizing the first and second data is adapted for having information scrolling in the banner areas of the display. A scroll engine is arranged for receiving the first and second data from the video source, and for grabbing chunks of the first data of the plurality of chunks and for storing the grabbed chunks in the storage means. The scroll engine comprises multiplexing means for multiplexing the second data with stored chunks of the first data, and is arranged for forwarding the multiplexed first and second data to the display.

FIELD OF THE INVENTION

The present invention is generally related to the field of passengerinformation systems for use in transportation vehicles, airports,railway stations and the like.

BACKGROUND OF THE INVENTION

In the field of passenger information systems more and more highresolution screens are being installed on board of trains, trams andlight rail vehicles. These panels are replacing lower resolution matrixdisplays, e.g. LED displays. This trend is facilitated by the increasedrobustness of these high resolution panels. In addition, thesevisualization devices are now available in different sizes. This easesthe integration in the passenger area of rail vehicles. Another enablerfor this tendency is the fact that embedded processors have become muchmore powerful and that they are now capable to drive these highresolution output devices.

The main advantage is that these high resolution displays (implementedas e.g. plasma or TFT screens) are capable of communicating moreinformation in an accessible way to passengers compared to other, oldercommunication means.

The basic set-up of such a system is depicted in FIG. 1. A video source(100) renders the data to be visualized on the display (200) using avideo link (105). In an advantageous implementation the video source isan (embedded) processor. Other possible implementations can be in FPGA,Video Integrated Circuit, Application Specific Integrated Circuit or bymeans of other digital video sources. In the majority of applications,the video source (100) is connected by means of one or morecommunication channels to an on board network (700). Via this networkcontext data and/or data to be visualized are pushed towards thevisualization engine (100). The number of tasks to be fulfilled by thisvideo source is typically substantial. A non-exhaustive list includesrendering of templates, decoding JPEG images, decoding of highresolution movie streams, layering, font rendering and handling ofnetwork communication. These tasks increase the processor loadextensively.

Some information to be shown will scroll over a certain area of thedisplay. The primary advantage of scrolling particular data is theability to display a larger amount of information than when stationarydata is used. As the data moves across a limited space, more informationcan be displayed and a constantly changing message is presented toreaders. Another advantage of scrolling information is that it is moreattention-grabbing than stationary data.

The data referred to is not restricted to plain text only (e.g.announcing the next stations on a certain route), but can be variouskinds of visual data (e.g. a logo, picture, icon, . . . ).

In addition, some applications require several areas that scroll data,referred to as scrolling banners in the remainder of this description.

In order to implement a smooth scrolling banner the following process isrequired. At first, the video source needs to render the data to bescrolled within the banner area. This can include font rendering,picture drawing, and so forth. As soon this is finished, in a secondphase this data is copied or moved to the memory of the device in chargeof the scrolling. This can be the render engine itself or an externaldevice. In a last, third stage the device needs to correctly start thescrolling and ensure that the movement is as smooth as possible overtime.

However, some technical difficulties arise when one wants to take intoaccount these three steps in order to realise smooth scrolling banner(s)on the visualization area while at the same time keeping the processorload at an acceptable level. In FIG. 2 different frames are beingdepicted to be visualized on the screen. In typical applications everyframe is visualized for approximately 16 ms. This time interval isreferred to as the period of the display's frame rate. In FIG. 2 frame jmight, for example, visualize some movie or other graphics (711). Framej+1 is completely different and includes a banner area (712). The bannershould not be visualized in the preceding frame j. The informationscrolls until frame n and the banner should disappear immediately inframe n+1. Therefore, synchronization between the visualization of thebanner area and the rest of the screen should be handled on frame level.The arrow (900) in FIG. 3 visualizes the direction wherein the data tobe visualized should move.

In addition, to allow the second phase in the process to implementsmooth scrolling, the video source should have access to a highbandwidth communication channel (124) to allow copying the area to bescrolled over time to storage means (800) of the scrolling device asdepicted in FIG. 4. Providing such a high bandwidth communicationchannel (124), however, involves an additional cost and requiresadditional processor power.

Beside the capability to allow transparent scrolling (i.e. scrollingwhereby data content is overlaid on top of other data content, whichalso remains at least partially visible), as depicted in FIG. 3, it isan absolute requirement to ensure a consistent smooth movement of thedata over the screen per time. No hiccups (i.e. halting of movementduring a short or longer period of time) are tolerated. The number ofpixels moved per frame must therefore be kept constant at all times.

In the art solutions are known for embedded hardware acceleration inmicroprocessors. However, absolute smooth scrolling (defined as aconsistent movement of data in a certain direction per frame) is notfeasible with current solutions. These high end processors cannot beapplied in applications where limited heat and power dissipation isrequired.

In WO2008/004189 a method is disclosed of transmitting a TV signalincluding an information ticker. A ticker refers to a scrolling displaywherein new data or information appears and enters a display area at oneend of the display screen (typically, the right hand side) and scrollsacross the display screen to the opposite end (typically the left handside) where it departs the screen. Examples of tickers include newstickers, stoke quote tickers and so on. The proposed solution overcomesthe limitations of known ticker solutions that do not offer anyflexibility in dealing with the ticker data on the user side. Accordingto the disclosure of WO2008/004189 first ticker data is embedded in avideo stream and second ticker data in a separate data stream. The videostream and separate data stream are next multiplexed and broadcasted ina television signal. The proposed solution allows the end user, i.e. theTV viewer, to deal with the ticker data in a flexible way.

Hence, there is a need for a solution wherein the above-mentionedproblems are overcome.

SUMMARY OF THE INVENTION

It is an object of embodiments of the present invention to provide for asystem that allows smooth scrolling of data content over an informationdisplay. More in particular, a system is needed wherein scrolling isperformed synchronously with the display's refresh rate. It is a furtherobject of the invention to present a system wherein the appearance anddisappearance of data content in information banners is performed atdeterministic time instants with frame level accuracy.

The above objective is accomplished by the solution according to thepresent invention.

In a first aspect the invention relates to a system for visualizing datacomprising a video source arranged for dividing first data to bevisualized in one or more banner areas in a plurality of chunks andarranged for outputting said plurality of chunks of the first data to bedisplayed and for outputting second data to be visualized as abackground whereon the first data is overlaid. The system comprises adisplay for visualizing the first and second data, said display beingadapted for having information scrolling over one or more dedicatedregions of the display. The system further comprises

storage means for storing at least a part of the plurality of chunks offirst data, and

a scroll engine arranged for receiving the first and second data fromthe video source and arranged for grabbing chunks of the first data ofthe plurality of chunks and for storing the grabbed chunks in thestorage means, said scroll engine comprising multiplexing means formultiplexing the second data from the video source with chunks of thefirst data stored in the storage means, said scroll engine arranged forforwarding the multiplexed first and second data to the display, wherethe chunks of the first data are shown scrolling in a banner in the oneor more regions dedicated for the scrolling banner overlaid on thesecond data.

By providing the scroll engine as described the load on the video sourcecan be substantially reduced. The video source divides the data to bedisplayed in a banner on the display into various chunks. The need foran additional high bandwidth communication channel between video sourceand memory is eliminated, since the scroll engine grabs data from thevideo source output and copies it in the storage means. The scrollengine is capable of multiplexing chunks of data for the banner area(s)stored in the memory and second data from the video source, said seconddata to be visualized outside the one or more banner areas as abackground. The multiplexed data is then forwarded to the display, wherethe chunks of the first data are shown scrolling in a banner in the oneor more banner areas overlaid on the second data.

In a most preferred embodiment the video source is adapted to add amarker to at least one chunk of the chunks of first data, whereby saidmarker at least comprises synchronization information.

Providing various data chunks with a marker, e.g. in the form of amarker line, is highly advantageous in that it allows for synchronousoperation on frame level. When the scroll engine receives a chunk offirst data and detects a marker line, information for achievingsynchronisation becomes available.

In an advantageous embodiment the marker is contained in a set of pixelsof the chunks of first data. In a preferred embodiment the colour of thepixels is indicative of the information contained in the pixels.

Advantageously, the marker comprises a header, a payload and a checksum.The payload comprises preferably at least one of the following elements:chunk width, chunk identification, coordinates of a part of said displaywhere first data is to be displayed, timing information.

In a preferred embodiment the scroll engine comprises control logicarranged for processing the markers in the chunks of first data. Thecontrol logic is advantageously arranged for performing on the chunks offirst data stored in the storage means a shift over a fixed number ofpixels per frame.

In another embodiment the scroll engine comprises a memory controllerfor controlling reading from and writing to the storage means.Preferably, the memory controller can be activated for writing ondetection of a marker in order to store the chunks of first data.

Preferably the multiplexing means is arranged for calculating themultiplexed data on a pixel-by-pixel basis.

In a particular embodiment the storage means is integrated in the scrollengine.

In one aspect the invention relates to a passenger information systemcomprising a system for visualizing data as previously described.

In a further aspect the invention also relates to a method forvisualizing first data in a banner on a display overlaid on second data,comprising the steps of

rendering in a video source the first and second data to be visualized,

dividing in the video source the first data to be visualized in one ormore banner areas in a plurality of chunks of the first data,

grabbing chunks of the first data of the plurality of chunks receivedfrom the video source and storing the grabbed chunks,

multiplexing the second data received from the video source and to bevisualized as a background, with stored chunks of the first data, and

forwarding the multiplexed first and second data to the display, wherethe chunks of the first data are shown scrolling in a banner in the oneor more banner areas overlaid on the second data.

Most preferably the method comprises a step of adding a marker to achunk of said plurality of chunks of first data, said marker at leastcomprising synchronization information.

For purposes of summarizing the invention and the advantages achievedover the prior art, certain objects and advantages of the invention havebeen described herein above. Of course, it is to be understood that notnecessarily all such objects or advantages may be achieved in accordancewith any particular embodiment of the invention. Thus, for example,those skilled in the art will recognize that the invention may beembodied or carried out in a manner that achieves or optimizes oneadvantage or group of advantages as taught herein without necessarilyachieving other objects or advantages as may be taught or suggestedherein.

The above and other aspects of the invention will be apparent from andelucidated with reference to the embodiment(s) described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described further, by way of example, withreference to the accompanying drawings, wherein like reference numeralsrefer to like elements in the various figures.

FIG. 1 illustrates a conventional system for displaying video content asapplied in passenger information systems.

FIG. 2 illustrates different frames to be visualized on a display.

FIG. 3 illustrates transparent scrolling.

FIG. 4 represents a conventional system with dedicated high bandwidthcommunication channel to access storage means.

FIG. 5 represents an embodiment of the solution according to theinvention.

FIG. 6 illustrates two chunks of data in a banner area.

FIG. 7 illustrates the described grabbing and multiplexing mechanisms inan example.

FIG. 8 represents a more detailed view on an embodiment of the scrollengine.

FIG. 9 illustrates a marker line in a slice of data.

FIG. 10 represents a banner scrolling in the indicated direction.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The present invention will be described with respect to particularembodiments and with reference to certain drawings but the invention isnot limited thereto but only by the claims.

Furthermore, the terms first, second and the like in the description andin the claims, are used for distinguishing between similar elements andnot necessarily for describing a sequence, either temporally, spatially,in ranking or in any other manner. It is to be understood that the termsso used are interchangeable under appropriate circumstances and that theembodiments of the invention described herein are capable of operationin other sequences than described or illustrated herein.

It is to be noticed that the term “comprising”, used in the claims,should not be interpreted as being restricted to the means listedthereafter; it does not exclude other elements or steps. It is thus tobe interpreted as specifying the presence of the stated features,integers, steps or components as referred to, but does not preclude thepresence or addition of one or more other features, integers, steps orcomponents, or groups thereof. Thus, the scope of the expression “adevice comprising means A and B” should not be limited to devicesconsisting only of components A and B. It means that with respect to thepresent invention, the only relevant components of the device are A andB.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure or characteristicdescribed in connection with the embodiment is included in at least oneembodiment of the present invention. Thus, appearances of the phrases“in one embodiment” or “in an embodiment” in various places throughoutthis specification are not necessarily all referring to the sameembodiment, but may. Furthermore, the particular features, structures orcharacteristics may be combined in any suitable manner, as would beapparent to one of ordinary skill in the art from this disclosure, inone or more embodiments.

Similarly it should be appreciated that in the description of exemplaryembodiments of the invention, various features of the invention aresometimes grouped together in a single embodiment, figure, ordescription thereof for the purpose of streamlining the disclosure andaiding in the understanding of one or more of the various inventiveaspects. This method of disclosure, however, is not to be interpreted asreflecting an intention that the claimed invention requires morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive aspects lie in less than allfeatures of a single foregoing disclosed embodiment. Thus, the claimsfollowing the detailed description are hereby expressly incorporatedinto this detailed description, with each claim standing on its own as aseparate embodiment of this invention.

Furthermore, while some embodiments described herein include some butnot other features included in other embodiments, combinations offeatures of different embodiments are meant to be within the scope ofthe invention, and form different embodiments, as would be understood bythose in the art. For example, in the following claims, any of theclaimed embodiments can be used in any combination.

It should be noted that the use of particular terminology whendescribing certain features or aspects of the invention should not betaken to imply that the terminology is being re-defined herein to berestricted to include any specific characteristics of the features oraspects of the invention with which that terminology is associated.

In the description provided herein, numerous specific details are setforth. However, it is understood that embodiments of the invention maybe practiced without these specific details. In other instances,well-known methods, structures and techniques have not been shown indetail in order not to obscure an understanding of this description.

The present invention presents a system for visualising text and imagecontent wherein an additional component is provided. On top of the partsalready shown in the prior art system of FIG. 1, the system comprises ascroll engine to handle scrolling of said data or text content indedicated regions on the display. Further, an additional feature hasbeen implemented in the video source, which gives the video source thecapability of adding a marker to a chunk of data to be displayed in abanner, whereby synchronisation information is comprised in said marker.

FIG. 5 illustrates this newly added component (300) together with anadapted video source (100) and the display (200). The scroll engine(300) has access to RAM memory (800) to store data to be visualized bymeans of an interface (130). This memory can be externally connected orcan be implemented within the scroll engine itself.

On the side of the video source (100), the data to be visualized intothe banner area is divided in different chunks, also referred to asslices, to be displayed sequentially on the display. In terms of numberof pixels, a slice is always smaller than or exactly as large as thebanner area. In FIG. 6 two slices are depicted. Slice 580, holding thecharacters ‘This is an’, is followed by slice 581 containing ‘example’.Both slices fit within the banner area (590) wherein the actualscrolling will take place.

The described process is depicted in FIG. 7 with an example. The firstrow represents the different frames j to frame j+r of the video sourceoutput (115). The area not including the banner area may alter in eachframe (e.g. displaying a video) and is directly forwarded to the scrollengine output (125). This is handled by the multiplexing device (310).

Within the scroll engine the scroll engine is capable of grabbing datadirectly from the video source output (115). Therefore the need for anadditional high bandwidth communication channel to connect the videosource with the memory is avoided. In frame j the first slice i iscopied by the scroll engine into the first memory location as depictedin the second row of FIG. 7.

In frame j the scroll engine outputs the data (115) received at thescroll engine input multiplexed with a banner area overlay. As soon asenough slices are received and stored into the storage means, the scrollengine starts multiplexing the input data (115) with the stored contentin memory (800). This is depicted in the third row of FIG. 7, frame j+k.Each time the output frame (125) is refreshed, the read pointer(indicated with marker r in FIG. 7) pointing to the location of thememory wherefrom data is read, is incremented with a constant valueaccording to the scroll speed in order to achieve smooth scrolling.

As soon as the memory is completely filled with chunks of data, thegrabbing process is halted until memory can be freed. This happens whena slice has been completely visualized, as is the case for slice i atframe j+n (FIG. 7). At this time memory is freed instantly and as soonas the video source again outputs a next slice to be stored, the scrollengine grabs and stores said chunk. This is depicted in frame j+q.

In the embodiment in FIG. 8 three main components can be identifiedwithin the scroll engine:

a memory controller (320) to allow reading from and writing to thememory repository (800).

a multiplexer (310) which calculates -on a pixel basis- the outputvalue, taking into account banner information stored in the memory,video source output (115) and other parameters (e.g. alpha value givinga measure (typically between 0 and 1) for transparency, e.g. alpha=0 iscompletely invisible and alpha=1 is completely visible) and

the control logic (330) which takes care of the algorithm described morein detail below.

To allow synchronization on frame level, as depicted in FIG. 2, thevideo source (100) is according to this invention adapted to add to thevideo stream (115) information referred to as marker lines.

FIG. 9 depicts a banner area and in it a slice (580). In the embodimentshown in the figure the pixels (561) of this slice area hold data whichwill be processed by the scroll engine. Details on the data are providedbelow. In this way exact synchronization is achieved and data requiredfor correct scrolling and visualisation on the display can becommunicated between video source (100) and scroll engine component(330) without the need of an additional communication channel.

The marker line comprises pixels which hold data by means of the colourof these pixels. For example, in a 6*3 bit per pixel system (e.g. an RGBsystem), each pixel can hold 18 bit of information. The marker linecomprises three main fields:

1/ a marker line header, which can serve as an ‘eye catcher’, so thatthe arrival of a marker line can easily be detected by the controllogic,2/ the payload carrying the data to be processed by the scroll engineand3/ a checksum, which is calculated taking into account the previousfields. The latter has been implemented to reduce the risk of a randomsequence of pixels (e.g. within a movie) being interpreted incorrectlyas a marker line whereby the scrolling process is triggered incorrectly.

In an advantageous embodiment the marker line may be configured asfollows. The header part comprises an eye catcher, which is aconsecutive number of pixels holding specific colours to ease thelocalization of the marker line within the data stream (115) by thescroll engine (300). The pay load includes at least one or more of:

marker line version

the background colour of the banner

the text colour of the slices

specific commands (examples are: scroller reset, scroller enable)

number of banner areas

scroll direction

slice identification

transparency value

banner coordinates (both to grab and to display)

slice width

timing (scroll speed)

Further, a checksum can be provided.

The requirement of smooth scrolling without hiccups can be met byshifting data a fixed number of pixels per frame. If this number variesover time, the scrolling is not perceived as smooth. However,implementing this feature in the video source would impose an unduecomputational burden on the video source. Therefore, in the presentinvention a realisation in hardware exploiting a scroll engine isproposed. The scroll engine of this invention complies with thisrequirement of smooth scrolling. It is noted that scrolling can beperformed in any direction, i.e. from left to right, from right to left,from bottom to top, from top to bottom or any meaningful combinationthereof.

The algorithm execution is supervised by the control logic (330) of thescroll engine (300) and comprises a number of consecutive steps. Thevideo input data is checked by the control logic on the existence of oneor more marker lines. If none exists, the video output (125) is equal tothe input video stream (115). If a marker line is detected, the controllogic parses the required data from its payload. If the banner shouldnot be transparent, the scroll engine lays an overlay over the bannerarea, using the background colour fetched from the marker lineinformation. At that moment the slice data is not visualized any longeron the display (125), but remains available for the scroll engine. Anexample is depicted in FIG. 7, row three, frame j. In the case oftransparent banners, data is grabbed from a non-visible part of thedisplay.

As soon as one or more marker lines are detected, the scroll enginegrabs the slices one by one and stores them in the available memory. Thewrite pointer (indicated with marker w in FIG. 7) points to the nextavailable memory space. If the memory is almost full, the storage willbe halted until data has been freed because it has been ‘shifted’ out ofthe visualization area and is not needed any longer.

As soon as one full slice is available in the memory, the scrolling canstart. In FIG. 10 the scrolling has actually started and the firstcharacters of the complete sentence “This is an example” are beingvisualized.

As soon as a certain marker line is no longer present in the inputstream, the control logic immediately removes the banner area(s). Inthis way, synchronization is achieved on frame level.

In certain embodiments more than one banner can be applied on a display.In that particular case each banner can be treated separately aspreviously described. For example, data for each banner are separatelychunked in slices smaller than or equal to the banner area and providedwith marker lines etc. Also the scroll speed can differ between two ormore instances.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, such illustration and descriptionare to be considered illustrative or exemplary and not restrictive. Theforegoing description details certain embodiments of the invention. Itwill be appreciated, however, that no matter how detailed the foregoingappears in text, the invention may be practiced in many ways. Theinvention is not limited to the disclosed embodiments.

Other variations to the disclosed embodiments can be understood andeffected by those skilled in the art in practicing the claimedinvention, from a study of the drawings, the disclosure and the appendedclaims. In the claims, the word “comprising” does not exclude otherelements or steps, and the indefinite article “a” or “an” does notexclude a plurality. A single processor or other unit may fulfil thefunctions of several items recited in the claims. The mere fact thatcertain measures are recited in mutually different dependent claims doesnot indicate that a combination of these measures cannot be used toadvantage. A computer program may be stored/distributed on a suitablemedium, such as an optical storage medium or a solid-state mediumsupplied together with or as part of other hardware, but may also bedistributed in other forms, such as via the Internet or other wired orwireless telecommunication systems. Any reference signs in the claimsshould not be construed as limiting the scope.

1-15. (canceled)
 16. A system for visualizing data comprising a videosource arranged for dividing first data to be visualized in one or morebanner areas in a plurality of chunks, arranged for rendering said firstdata and second data to be visualized as a background and arranged foroutputting said plurality of chunks of said first data to be displayedand for outputting said second data to be visualized as a background, adisplay for visualizing said first and second data, said display beingadapted for having information scrolling in said one or more bannerareas of the display, said system further comprising storage means forstoring said first data, and a scroll engine arranged for receiving saidfirst and said second data from said video source and arranged forgrabbing chunks of said first data of said plurality of chunks and forstoring said grabbed chunks in said storage means, said scroll enginecomprising multiplexing means for multiplexing, once enough chunks ofsaid first data have been stored in said storage means, said second datawith stored chunks of said first data from said storage means, saidscroll engine arranged for forwarding said multiplexed first and seconddata to said display, where the chunks of said first data are shownscrolling in a banner in said one or more banner areas overlaid on saidsecond data, said scroll engine further comprising a read pointer forpointing to a location in said storage means wherefrom said first datais read, said read pointer being incrementable with a constant valueaccording to a scroll speed so that smooth scrolling is obtained. 17.The system for visualizing data as in claim 16, wherein said videosource is adapted to add a marker to a chunk of said plurality of chunksof first data, said marker at least comprising synchronizationinformation.
 18. The system for visualizing data as in claim 17, whereinsaid marker is contained in a set of pixels of said chunks of firstdata.
 19. The system for visualizing data as in claim 18, wherein thecolour of said pixels is indicative of the information contained in saidpixels.
 20. The system for visualizing data as in claim 18, wherein saidmarker comprises a header, a payload and a checksum.
 21. The system forvisualizing data as in claim 20, wherein said payload comprises at leastone of the following elements: chunk width, chunk identification,coordinates of a part of said display where first data is to bedisplayed, timing information.
 22. The system for visualizing data as inclaim 17, wherein said scroll engine comprises control logic arrangedfor processing said markers in said chunks.
 23. The system forvisualizing data as in claim 22, wherein said control logic is arrangedfor performing on said chunks of first data stored in said storage meansa shift over a fixed number of pixels per frame.
 24. The system forvisualizing data as in claim 16, wherein said scroll engine comprises amemory controller for controlling reading from and writing to saidstorage means.
 25. The system for visualizing data as in claim 24,wherein said memory controller can be activated for writing on detectionof a marker.
 26. The system for visualizing data as in claim 16, whereinsaid multiplexing means is arranged for calculating said multiplexeddata on a pixel-by-pixel basis.
 27. The system for visualizing data asin claim 16, wherein said storage means is integrated in said scrollengine.
 28. A passenger information system comprising a system forvisualizing data as in claim
 16. 29. A method for visualizing first datain a banner on a display overlaid on second data, comprising the stepsof rendering in a video source said first and second data to bevisualized, dividing in said video source said first data to bevisualized in one or more banner areas in a plurality of chunks of saidfirst data, grabbing chunks of said first data of said plurality ofchunks received from said video source and storing said grabbed chunksin a storage means, multiplexing, once enough chunks of said first datahave been stored, said second data received from said video source andto be visualized as a background, with stored chunks of said first data,and forwarding said multiplexed first and second data to said display,where the chunks of said first data are shown scrolling in a banner insaid one or more banner areas overlaid on said second data, whereby eachtime an output frame is refreshed, a read pointer to a location in saidstorage means wherefrom said first data is read, is incremented with aconstant value according to a scroll speed, so that smooth scrolling isobtained.
 30. The method for visualizing data as in claim 29, comprisingadding a marker to a chunk of said plurality of chunks of first data,said marker at least comprising synchronization information.